Carburetor



N. LOMBARD CARBURETOR Dec. 4, 1928. 1,693,793

Original Filed July 11. 1924 .Zizvani'bf: .lfii'hanzlel Lombard.

Patented Dec. 4, 1928.

UNITED STATES PATENT 'OFiFi-IC E.

NATHANIEL ILOMBALRD, or woncns'rnn, MASSACHUSETTS, .ASSIGNOR T0 .LOMBARD-mssaonusnrrs.

, CARBUBETER COMPANY, OF WORCESTER, MASSACHUSETTS, VA CORPORATION OF"CARBUREIOR.

Application'file'd July 1 1, "1924, Serial No. 725,500. RenewedDecember'17, 1927.

My invention relates to carburetors for use with internal combustionenginesand'the like to form the explosive mixture of air and fuel usedtherein. invention is to produce an improved form of carburetor adaptedto control theflow of fuel from the main supply tank to the engine,without the use of a pump or equivalent, so that the mixture at theengine intakenianifold :for any given condition of load, throttleposition andengine speed, will be practically -=constant, irrespectiveoft-the level of the main fuel-supply in relation to the carburetor,within reasonable limits.

More specifically, I have found that when my improved carburetor isproperly 'adjusted with the engine running, the main fuel tank maybetaken "and raised'above the level of the carburetor as much 'as twofeet, or lowered below the level of the car buretor as much as six orseven feet, and the engine will continue at the same speed and developthe samehorsepower. t is possible t make-such a test by using a flexibleP P Thus my carburetor is particularly adapted for aeroplane engines,and automobile engines, with the gasoline tank at the rear, if desired,no pump'or vacuum tank being necessary, and the automobile engine willoperate'on the steepest hill met with the same efficiency as on thelevel.

This application is a continuation, in part I at least. of mycopendingapplication Serial No. 656,774, filed Aug. 11, 1923, and in a divisionalapplication Serial No. 69, 22, filed November 16, 1925, I claim certaincombinations herein described, the claims of the present applicationbeing confined to the supply chamber, the bellows, valve device andassociated parts.

The above and other advantageous featuresof my invention willhereinafter more fully appear, reference being had to theaceompanyingdrawings, in which Fig. iis a vertical sectional view of acarburetor-embodying my invention.

' Fig. 2 is a horizontal sectional view along the line 2 2 of Fig.1,looking in the direction-of the arrows. p 1

Fig. '3 is a horizontal sectional view along the line '3-3 of Fig. 1,looking in the direc tio n of the arrows.

The object of my ingl'. terminatesin a-tapering-or ogee portionll,

Like reference characters refer to like parts in the-diiferent figures.

Referring to Fig. 1, the casing or shell-of the carburetor is generallyindicated at -1 and provides the usual flange 2*to facilitate1ts.:attach1nent-to the intake manifold of the engine, not shown. Airenters the'carbul'etor at 3 and passes through a 'Venturi passagea,-on'1ts way tothe engine. :I show the .usual throttle =valve at 6.Afhollow cylindrical valve casing 7 is secured to the shell 1 belowthe'air-chaniber 3, within which'fits a hollow piston 8. The piston 8 isprovided with a'reduced portion 9slidable within a.

sleeve. 10 extending upwardly from the cas- The reduced portion9 of thepiston around which a collar 12 tightly -fits,'and

the "latter seats in the throat of the Venturi passage. The parts '11and '12, .by their form, materially heightenlthe Venturi effect whenthey are slightly withdrawnfrom the throat- A coiled spring 13 isreceived within the portion 9 of the piston *8, and is seated atitslower-end on-a plate 14:. closing wardly from a boss 17 located" at thetop of the shell 1. The lower end of the stem 16 forms a needlevalvegproper "18, which extends into the constricted opening '19 of atube 20 carriedby the tapering portion 11.

IAbove the tube '20 is a space 21 in'thetaper- 121g portion, and thisspace is connected to the Venturi passage by means of a member of radialand axialpassagesfZEZ formed :by drilling the tapering portion 11 andgroov- The tube 20 extends downwardly into a ;sleeve 23 projectingupwardly'from th'e plate' 1 1:, and the lower end of tube 20 carries apiston '24, which is slidable within a hollow cylindrical casing '25which extends below the plate 14. It will be apparent-thatthe part-s8,"9,11, 12, 20 and 24: are attached together as .a unit, and when "theymove they move as such.

fing its sides before the collarv 12 is :fitted on.

28. The plate 26. is also provided with pas sages 29 extendingradiallyfrom the openmg 27, which passages 29co1nmnnicate w1th passages30 extendin g upwardly through the walls of the casing 25,- whereby thesmall space 31 above the top of the piston 24 is in communication Wltlithe opening 27. The space31 is also in communication with the interiorof the tube through a restricted passage 32 provided in the wall of thetube 20, for a purpose to be hereinafter described.

The tapering portion 11 is also grooved to provide a number of axialpassages between it and the collar 12, as in the case of axial passages22, but the two sets of passagesare not intercommunieating. The passages33 connect the Venturi passage 4 with the interior :of'the hollow piston8 and the chamber inclosed within the casing 7 Fig ure 2 shows therelative arrangement of jpassages 22 and 33. The space 34 above thepiston 8 is in communication with the outside atmospheric pressure, inany suitable manner, such asa groove along the portion 9, or a holethrough the horizontal portion of the sleeve 10 at 34 When a suction iscreated by, the engine, the interior of the piston 8 will be subjectedto this suction, it being communicated by the passages 33, whereupon thepiston S will.

move downwardly against the force of the spring 13. Such downwardmovement will allow a draft of air, entering at 3, to. go throughtheventuri 4 to the engine, and at the same time, the needle valve'proper18 and the tube 20 having been separated, fuel is sucked through thepassages 22 and mixes with the air. g

It will be noted that the passages 22 open into the venturi4'practically at the point of maximum air velocity, and thesuction thuscreated will lift fuel from a tanlr sev eral feet below this point. Inthe use of my improved carburetor with automobile engines, it is notsuiiicient, however, merely to lift the fuel, but the flow thereof mustbe controlled and regulated, andby my invention I have provided meansfor regulating the flow that is essentially dynamic in its action, sothat the results hereinbefore mentioned may be achieved. 7 r i 5Proceeding with the description of parts,

the plate 26 provides a nipple having an opening 36 in communicationwith the opening 27, and the nipple 35 is surrounded by a coupling 37having a passage '38 extending therethrough, in communication withthenipple opening36. The coupling 37 provides a cup-shaped portion 39,-into which the passage 38 opens, and the portion 39.

serves as a base for a shell 40, thereby providing an inclosed chamber41 in direct communication with the o ening 27 in the bottom plate 26 ofthe car ureter. An expansible diaphragm bellows device 42 is locatedwithin the shell 40. The upper end of the bellows 42 is, carried by anipple 43 in threaded engagement with a nut 44 se cured to the top ofthe shell 40, allock nut 45 cooperating with the nipple The nipple 43has a passage 46, and I desirably .tact with a ball provided at theupper end of a valve stem 51. The valve stem51 extends downwardly intoair opening 52 pro vided in the coupling 37, the stem 51 being providedat its lower end with a valve53. Thevalve stem 51;is carried by a spring54 just below the ball 50.which, when the en glue is not runnmg,servestomaintain the valve .53 in engagement with a" seat 55, there by closingthe opening 52, That portion of the opening 52 below the valve seat 55is connected by a pipe 56 to a supply tank 57,

only a portion of which is shown. In the operation of the improvedcarburetor, the needle valve mechanism described opens more or less inresponse, to the extent of suction created by the engine, the needlevalve of the venturi and the action of the piston 8. However, the saidneedle valve mechanism will not respond separately to. each strok of theengine on account of the dampingw action of the piston 24. If, however,an enwith the carburetor of the present invenphragm controlled valve 53to allow a given .mechanism being very sensitive on account loo ginewith six ormore cylinders is equipped quantity offuel per unit of timeto be con;

sumed by the engine for a given engine speed and setting of thethrottle6, in other words,

for agiven suction, irrespective of the exact head offuel between thesurface of fuel in tank 57 and the valve 53 (within reason ably widelimits) for the following reason: 7

Ifthe said head is diminished for any cause, the diaphragm 42,whichresponds to V a differential between thisfthead, considered.staticallyand the effective suction on the needle valve mechanism,closes the valve 53 frictional effect tends to. close thevalve 53 stillfurther, This may be properly called a dynamic effect, and the result isthat whatever. the exact heightflof the fuel in the tank I Y 57 theaforesaid static and dynamic forces combine'with the action of theneedle valve mechanism to perfectly control the supply of fuel.

Additional features of the invention reside in the fact that the stem 51is held rigidly far as sideways motion is concerned, and will notpartake of any vibration in a horizontal plane induced by the diaphragm4:2, owing to the separation between the seat and ball 4-9 and 50.

Also it will be noted that if for any cause the chamber 41 should becomeflooded, the diaphragm 42'would immediately collapse, owing to thehydrostatic action of the fuel, and prevent further fuel. entering thechamber ll until the level had been lowered. This action is however,usually induced be fore the actual touching of the diaphragm 42 by thefuel, owing to a compression of air within said chamber 41. The factthat very little fuel is kept, at any time, in the chamber 41,rendersthe carburetor exceptionally safe from the standpoint of firehazard.

It may be observed that statically considered there would seem to be noreason why fuel should ever rise into the chamber 41, but the flow pastthe valve 53 is sufficient in velocity to cause it to rise; at any rateactual experiment shows that it does so rise during operation normallyto about the lower dotted line position in Fig. 1, while under unusualconditions, it has been observed to rise as far as the upper dotted lineposition.

Having thus given an illustrative embodiment of my invention togetherwith the re sult achieved which is, so far as I am aware, new, andsurely highly useful, and having attempted an explanation of thephysical laws which coact with the means shown to effect the desiredresult, it must be understood that the correctness of the saidexplanation is not guaranteed, but seems to me plausible, while theresult has been proved by experiment, and the means is clearly shown anddescribed. Therefore,'I do not wish to be limited to the particular formof the invention herein shown, the scope of my invention being properlyset forth in the appended claims.

I claim:

1. In a carburetor, a supply chamber for liquid fuel, a valve forcontrolling the admission of fuel to said chamber, a fiat spring in aplane substantially perpendicular to the movement of said valve forholding said valve in its closed position and for substantiallypreventing sidewise vibration of said valve, and an ezpansible diaphragmlocated wlthin sald chamber, said diaphragm being provided with a seatadapted to engage a the bottom an exoansible bellows device in saidchamber adapted to expand in response to decrease of gaseous pressure insaid cham ber, the interior of said bellows device being open to theatmosphere, and a valve device for admitting liquid fuel to said chamberoperatively connected to said bellows and adapted to be opened uponexpansion of said bellows, the parts being so arranged that upon thefuel in said chamber reaching a predetermined level the hydrostaticpressure thereof operates to contact said bellows and close said valvedevice, thus keeping a minimum of fuel in said'chamber.

3. In a carburetor, afuel supply chamber, an entrance orifice for saidchamber, an exit orifice for said chamber, both orifices being low pointin said chamber, anexpansible pneumatic device, the interior of which isopen to the atmosphere, in said chamber, a valve controlling entrance ofliquid at said entrance orifice under the control of said pneumaticdevice, whereby eX- V pansion of the latter openssaid valve and.

determined low point in said chamber it acts hydrostatically on saidpneumatic device to close said valve.

4. In a carburetor, a supply chamber for liquid fuel, an expansiblebellows device rigidly attached to the top of said chamber, a valve inthe lower pa-rt'of said'chamber, guiding means holding said valve fromvibration, and concave and convex surfaces, one carried by the lowerpart of said bellows, the other carried by said valve, whereby the lowerpart of the bellows is held from side ways vibration by the meansguiding said valve, and whereby said bellows, on eXpan sion, pushes saidvalve downwardly, thus opening it, said valve and said bellows, when thelatter is contracted, being unconnected.

Datedthis third day of July, 1924.

NATHANIELLOMBARD;

V, V, ,h/w i CERTIFICATE OF fiOiRRECTION Patent No. 1,693,793. I GrantedDecember 4, 1928, to

NATHANIEL LOMBARD.

It is hereby certified that error apgioars in the printed specificationoi. the above numbered patent requiring correction as follows: Page 3,line 79, claim 2, ior'the word "contact" read "com-mot"; and that thesaid Letters Patent Should he read with this correction therein that thesame may conform to the record otthe case in the Patent Office.

Signed and sealed this. 8th day of January, A. D. 192).

Mi .1. Moore, (Seal) Acting Commissioner of Patents.

